Hi Class! This week, we learned the interaction of nano-or micro-scale biomaterials with cells and the interaction of cells/tissues/organism with large scale biomaterials at both the cellular level and the tissue/host level. In this blog, I am going to talk about cell interactions with nano-patterned implants with a focus on implants made of metallic materials.
Metallic materials are often used for fabricating orthopedic and dental implants because their surfaces are biocompatible with tissues at the target area. Some commonly used surface modification methods for metals include grid-blasting, acid etching, chemical grafting, ionic implantation and calcium phosphate coatings. These strategies for modifying the nature of this interface usually involve changes to the surface at the nanometer level, thereby affecting protein adsorption, cell–substrate interactions, and tissue development.
Figure 1: Tissue – dental implant interactions at both gingival and bone sites.
For example, anodization of titanium implants can yield features of nanometer size dimensions . This is achieved by developing a titanium oxide layer using a platinum counter electrode in acidic solutions at a potential of 5-25 V. Through changing experimental conditions (i.e. potential, temperature, electrolyte), scientists have produced an oxide layer a few microns in thickness and composed of a regular array of nanometer sized pores with diameters in the 30-100 nm range, growing perpendicular to the titanium surface. The pore sizes are compatible with those of proteins such as fibronectin (FN) and vitronectin which play an important role in cell adhesion, as discussed in class.
In a nutshell, careful preparation of standardized nanostructured surfaces with repetitive topography may elicit protein adsorption, cell response and cell differentiation. Further research aiming at correlating cell behavior and tissue integration in the future will help us understand the role of surface nanostructures in these biological responses. It is possible to imagine controlling peri-implant tissue healing by changing the surface properties at the nanometer scale.
References:
[1] Lavenus, Sandrine, et al. “Cell interaction with nanopatterned surface of implants.” Nanomedicine 5.6 (2010): 937-947.
[2] Ratner, Buddy D., et al. Biomaterials science: an introduction to materials in medicine. Elsevier, 2004.